Approach to Respiratory Disorders

Anatomic and Physiologic Considerations

• The respiratory system includes the central nervous system, chest wall, pulmonary circulation, and respiratory tract.
• Bronchial branches function as conducting airways; gas exchange occurs from respiratory bronchioles to alveoli in the respiratory zone.
• Alveoli predominantly contain flat type I pneumocytes; type II pneumocytes (around 5%) are thicker and secrete surfactant.
• The right lung features three lobes (upper, middle, lower), while the left lung has two lobes (upper, lower), each divided into segments.
• The lungs' primary function is gas exchange, processing the entire cardiac output to absorb oxygen and remove carbon dioxide.
• Adequate gas exchange relies on factors like cardiac output, alveolar ventilation, surface area, and matching blood flow to ventilation.

Ventilation Mechanics

• Ventilation involves the movement of air in and out of the lungs.
• Inspiration requires active contraction of respiratory muscles, expanding intrathoracic volume and drawing air in.
• Exhalation is typically passive through relaxation of inspiratory muscles; active contraction may be necessary in conditions like emphysema.
• The diaphragm serves as the primary respiratory muscle, with accessory muscles (intercostal, sternocleidomastoid, scalene, abdominal) contributing minimally under normal conditions.
• Serious respiratory disorders in children, such as severe asthma or cystic fibrosis, can delay growth and development.

Examination of the Thorax

• Organized thoracic examination consists of inspection, palpation, percussion, and auscultation.
• During inspection, observe the rate and pattern of breathing, note any chest wall deformities, and assess respiratory movement symmetry.
• Impairment in respiratory movement could indicate conditions like fibrosis or pleural effusion; retraction often seen in severe asthma or COPD.
• Palpation assesses tenderness and fremitus, which is a vibration felt during speech; decreased fremitus can indicate pleural effusion or pneumothorax.
• Percussion distinguishes between air-filled, fluid-filled, or solid underlying tissue; dull sounds suggest conditions like pleural effusion or lung consolidation.
• Respirophasic chest pain increases with breathing and pressure application; termed pleuritic pain.

Causes of Chest Pain

• Central Causes: Cardiac (myocardial ischemia, infarction), aortic (dissection, aneurysm), esophageal (oesophagitis, spasm), massive pulmonary embolism, mediastinal (tracheitis, malignancy).
• Peripheral Causes: Lung/pleura issues (pulmonary infarct, pneumonia, pneumothorax), musculoskeletal problems (osteoarthritis, rib injuries), neurological concerns (herpes zoster, thoracic outlet syndrome).

Additional History

• Gather past medical history and social history, focusing on smoking habits and environmental exposure.
• Assess smoking: intensity, duration, and first cigarette's timing as indicators of addiction severity.

Physical Examination

• General appearance is crucial in patients with respiratory symptoms; distress may indicate severe illness.
• Look for signs of respiratory distress like cyanosis or difficulty speaking in complete sentences.
• Body habitus provides insight; obesity is linked to various respiratory conditions, while cachexia may signal cancer or AIDS.

This quiz explores the anatomical and physiological considerations of the respiratory system, focusing on its components and their roles. Participants will learn about the conducting airways and the mechanisms of gas exchange within the respiratory zones. Test your knowledge on the complexities of respiratory disorders.